The present invention relates generally to shoes and specifically to shoe sole construction. The increased popularity of competitive and recreational running, witnessed in the last few years, has resulted in the introduction of a wide variety of athletic shoe designs wherein shoe upper and sole constructions have embodied changes directed toward specific objectives. For example, in the prior art is shoe sole construction having "flared" side edges extending continuously about the heel portion ostensibly for supplementing heel stability, and sole constructions with tread designs directed toward minimizing impact loads on the foot and leg.
To the extent the prior art is known, efforts have been made to provide soles for athletic shoes with the sole having cupped tread surfaces with the outer tread surfaces being continuous in order to affect a momentary seal between the sole and floor for traction purposes. Examples of such efforts are found in indoor type athletic shoes in U.S. Pat. Nos. 1,962,526 and 2,071,431. Neither of the foregoing patents disclose multiple lug series in proximity of both sole edges. Additionally, U.S. Pat. No. 3,100,354 discloses a shoe sole having a lengthwise orientated concavity but significantly different from the present invention in that the concavity is laterally defined by the flat sole surfaces of considerable width, and in similarity to the first mentioned patents does not utilize laterally spaced series of tread components with each series of an effective different height. U.S. Pat. No. 4,085,527 shows intermingled cleats.